Well, after some development an initial version of g-metrics.com is on-line!
What it basically does is to keep track of the "googlecount" of various terms. If you register, you can add your terms too in the database, and watch their googlecount as it changes from day to day.
The "google query" string can be anything (I think) you would use in the google search box. So, one could keep track of the number of links to a page (by using "link:www.domain.com/page"), in addition to a "normal" search...
There is much to be done, much to improve, but ... well.. it works!